The annual Cystic Fibrosis fundraising event that Rob Olson holds at his Lake Elmo, Minn., home tends to rake in big bucks. But this year, it'll score nothing: Olson (pictured above) had to cancel the fete because he accidentally killed his entire lawn, a TV station reported.

Olson, who founded a fundraiser for the Cystic Fibrosis Foundation, was simply using a weed killer to spruce up his lot before the charity event. But shortly after spraying the product on his lawn, it began to die -- all 40,000 square feet of it.

Olson used a spray (pictured at left) manufactured by Ferti-lome, acting on the advice of employees at the Dege Garden Center, KARE 11 reported. But shortly after using it, his grass began to die.

Olson called the store to complain, and that's when he learned that the Ferti-lome product contained agents that kill grass -- and prevent affected areas from being reseeded or sodded for up to six months, according to the KARE 11 report.

A Ferti-lome spokesperson told KARE 11 that a booklet attached to the back of the product's bottles contain instructions "related directly to the product." Indeed, the second page of the booklet contains a warning not to use it on "desirable plants or lawns." On the front of the bottle, there is a reference to "weed and grass control."

"I think the packaging should say right on it: 'This will kill your lawn,'" Olson told Kare 11, adding that the warning in the booklet should be made more prominent on the bottle.

Olson, who has two sons who suffer from Cystic Fibrosis, said that his annual fundraiser brought in $20,000 last year. He added that he contacted "probably 15 different places" to reschedule the event but couldn't find a place.